When ever a chicken dies it has to refrigerated immediately not frozen. I live in oklahoma and the county extension picked up the bird within two days of it demise. It was free. They stated they were doing them to monitor any infectious diseases like newcastle.
It is so hard to see them doing better and then they die. It happens a lot unfortunately. I tell my daughter that if all the chicks lived we would be up to our elbows in chickens. Seems to help us to think of it that way.